Re: DB Block Buffers - Too Much ???

From: Deepak Sharma <sharmakdeep_at_yahoo.com>
Date: Wed, 21 Jun 2000 11:54:47 -0700 (PDT)
Message-Id: <10535.110051@fatcity.com>

Since I don't see a '0', does it mean I need to further increase db_block_buffers ?

• Mike Killough <mwkillough_at_hotmail.com> wrote:
  > No, 0 = free. 1 = read and modified
  >
  >
  > >From: Deepak Sharma <sharmakdeep_at_yahoo.com>
  > >Reply-To: ORACLE-L_at_fatcity.com
  > >To: Multiple recipients of list ORACLE-L
  > <ORACLE-L_at_fatcity.com>
  > >Subject: DB Block Buffers - Too Much ???
  > >Date: Wed, 21 Jun 2000 09:26:00 -0800
  > >
  > >Recently on one of our test systems the Buffer
  > Cache
  > >Hit Ratio was showing 80%. I increased
  > >db_block_buffers from 6000 to 16000, and the after
  > >that the hit ratio has dropped to 55%. It seemed
  > >strange to me that increasing db_block_buffers
  > should
  > >actually decrease performance, until I read Oracle
  > >tuning tips from Richard Niemiec, where he mentions
  > >too much db_block_buffers is not good too, as it
  > may
  > >lead to swapping. My question is how do you
  > determine
  > >whether the buffers are too low or too high ?
  > >
  > >SQL> select state, count(*) from x$bh group by
  > state;
  > >
  > > STATE COUNT(*)
  > >---------- ----------
  > > 1 13047
  > > 3 2953
  > >
  > >Does state = '1' mean this memory is not being used
  > >and if so, should I decrease the buffers ?
  > >
  > >-- Deepak
  > >
  > >=====
  > >Oracle DBA,
  > >Minneapolis, MN
  > >USA
  > >
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  > >Author: Deepak Sharma
  > > INET: sharmakdeep_at_yahoo.com
  > >
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Received on Wed Jun 21 2000 - 13:54:47 CDT